The present invention relates in general to methods and apparatus for monitoring the operation and use of a machine. More particularly, the present invention relates to methods and apparatus for monitoring the operation and use of a machine for the purpose of diagnosing the mechanical condition of the machine based thereon.
It is known to monitor machine operation parameters, such as, for example, machine vibration, temperature, sound, force or pressure, motor current or lubricant oil temperature, viscosity or composition, and to evaluate such monitored parameters for the purpose of providing an indication of the condition of the machine. For example, a thermocouple may be located within the lubricant “bath” so as to alert the machine operator when the temperature of the oil has exceed some predetermined threshold value. In another example relating to machine vibration, techniques employed to monitor and to analyze machine vibration for the purpose of providing an indication of the condition of the machine range from the very simple, such as touching or listening to a machine, to the very complicated, such as detecting time-domain signals, converting those signals to frequency-domain signals, and computer-processing the resulting frequency domain signals. Techniques at the lower range of the monitoring and analysis spectrum are overly-simplified and do not provide reliable results whereas techniques at the upper range of the spectrum are overly-complicated and are typically so expensive so as to prohibit their widespread use by most machine operators.
Accordingly, there is a need for new and improved monitoring and analysis techniques for providing an indication of the condition of a machine, such as an indication of the general “health” of the machine by providing a running history or profile of the machine's operation or usage. Preferably, such monitoring and analysis techniques would provide reliable results, would be easy to use, would be relatively inexpensive and would be adaptable to improve the operating practices of the machine, such as, for example, as one component of the machine operator's predictive/preventative maintenance procedures. There also is a need for new and improved analysis techniques for providing an indication of the useful “life” remaining in a machine, based upon actual past machine operation and usage.